Study on the effect of PVP additive on the performance of PSf/PVP ultrafiltration hollow fiber membrane

Abstract

Asymmetric, porous ultrafiltration polysulfone (PSf) hollow fiber membranes were fabricated based on different compositions of polyvinylpyrrolidone (PVP) additive concentration. The physical structure or morphology of a fabricated membrane is a major concern in determining the efficiency of a dialysis membrane. Different types of membrane morphology will give a different result in terms of membrane permeability and clearance efficiency. The phase inversion spinning technique is suitable in producing ultrafiltation (UF) membrane where the average pore size of the fabricated membrane is in the range of 0.001 – 0.1 μm. However, there are many factors need to be controlled and manipulated during the phase inversion technique. In this study, the effect of the PVP on membrane pore size and performances were analysed. The contact angle was measured to determine the hydrophilicity of the membranes. The hydrophilic polymer is favorable to avoid fouling and to increase membrane biocompatibility. Furthermore, the diameter of the membrane fibers was determined using a scanning electron microscopy (SEM). The effects of different morphologies of the hollow fibers on the performance of the membranes were evaluated by pure water flux and BSA rejection. Both experiments were conducted using permeation flux system. It was found that the finger-like macrovoids in PSf hollow fiber membranes were suppressed by the addition of 8% PVP (Mw of 360 kDa) as the result of a drastic increase in dope solution viscosity. On top of that, the fibers spun with 8% PVP showed a more porous structure which contributes to higher membrane permeability.